(Pattern Evidence)




             This is forensic science work at the qualified examiner level in the preservation, examination, handling, and comparative analysis of items of evidence collected in criminal investigations.  Positions in this class are allocated to one of three specialties: Biology, Chemistry or Pattern Evidence.  Positions allocated to the Pattern Evidence specialty are assigned to one of the following disciplines: Documents, Firearms/Toolmarks, or Latent Prints.  An employee in this class is assigned progressively more difficult work tasks and is expected to work independently on casework and assumes greater responsibility as experience is gained.

             Work in each specialty includes examining evidence associated with crimes for presentation of laboratory findings in written reports and through expert testimony in criminal trials. As experience is gained, assignments increase in scope and complexity.  All work is performed in accordance with national and international quality assurance standards in the accredited Forensic Science Bureau of the Philadelphia Police Department. Work is performed under the supervision of a higher-level forensic scientist or technical superior.


ALLOCATING FACTORS: (The following conditions must be met for a position to be allocated to this class.)


·         Employees in this class must perform biology, chemistry or pattern evidence work at the qualified examiner level.

·         Positions must be located in the Forensic Science Bureau of the Philadelphia Police Department.






·         Performs the duties of the specialty/assignment at the qualified examiner level.

·         Prepares reagents used in the area of specialty/assignment.

·         Logs in samples in compliance with departmental and national forensic accreditation procedures.

·         Stores samples according to proper established protocols.

·         Maintains data records; prepares reports.

·         Communicates findings and conclusions with investigators and attorneys.

·         Maintains compliance with all quality assurances standards for forensic accreditation.

·         Determines the type and order of forensic examination to perform.

·         Collaborates with other experts in the FSB to ensure that all integrated examinations across disciplines are performed when required.

·         Prepares technical reports on findings and projects; studies pamphlets, journals, and books for use in devising methods an tests

·         Follows evidence control procedures to maintain chain-of-evidence integrity; insures evidence is locked securely in designated locker or space before and after analysis.

·         Operates computer consoles to analyze results of tests or to perform mathematical calculations involved in the analyses of evidence.

·         Checks instrumentation for validity and reliability against standards and recalibrates.

·         Provides expert testimony on examinations in criminal trials.

·         Participates in research projects by performing routine tests.

·         Provides presentations in the assigned discipline.

·         Participates  in regular training and competency testing.

·         Performs related work as required.




Examines physical evidence for trace materials to be tested with presumptive and confirmatory procedures, including but not limited to, those for the presence of blood, semen, saliva, hair, and other biological material.

Extracts DNA from various biological samples (i.e. blood, semen, saliva, etc.) using DNA extraction techniques, such as, Chelex and organic methods; amplifies extracted DNA for particular genetic markers using PCR technology.

Establishes genetic profiles for biological samples collected from crime scenes and reference samples collected from suspects/victims through the use of standard molecular biology techniques, equipment and software, such as capillary electrophoresis analyzers and GeneMapper; compares genetic profiles established from scene samples to genetic profiles established from reference samples.

Performs basic statistical calculations to determine frequencies of matching profiles and advanced statistical calculations to evaluate biological relationships associated with kinship.

Performs related work as required.




            Collects and analyzes samples of liquid, solid, and gaseous materials, substances and compounds for qualitative and/or quantitative results.

            Analyzes macroscopic and microscopic suspected substances for presence of illegal elements, by use of traditional and instrumental chemistry techniques; identifies controlled substances, precursors, by-products and other substances used for drug dilution; examines and identifies suspected drug paraphernalia; analyzes foodstuffs for the presence of foreign materials such as drugs and poisons, and identifies possible poisons; analyzes urine for drug content and quantifies concentrations; collects evidence samples and prepares facilitating tasks for higher-level chemists at clandestine laboratory scenes. 

            Analyzes samples with wet chemistry methods or standard laboratory equipment and/or advanced instrumentation, such as, atomic absorption/emission spectrophotometers, gas/liquid chromatographs, UV-visible, infra-red spectrophotometers, mass spectrometers, scanning electron microscopes, compound microscopes and/or any related equipment.

Performs related work as required.




Document Assignment


            Examines, classifies and/or compares documents, papers, checks, stickers, stamps, impressions, handwriting and other related evidence; utilizes advanced techniques to restore or visualize identifying marks and obliterated or altered evidence.

Performs related work as required.


Firearms/Toolmarks Assignment


            Examines, classifies and/or compares firearms, ammunition, tools, toolmarks, and other ballistics evidence; checks files to ascertain if recovered weapons have a previous record of being stolen or wanted as evidence.

Utilizes advanced techniques to restore identifying marks or serial numbers, which may have been obliterated; performs comparative analysis on various comparison microscopes and documents findings through photomicrography and written notes.

Test fires weapons and performs safety checks.

Performs related work as required.


Latent Print Assignment    

            Examines and classifies incoming fingerprint impression evidence; enters work received into a computerized tracking program.

            Evaluates and enters suitable latent prints into an Automated Fingerprint Identification System (AFIS) for searching; uses AFIS results to pull files for manual comparison

            Makes decisions of individualization based on ACE-V scientific methodology.

Performs related work as required.








·             basic laboratory techniques and the techniques and equipment used in a forensic laboratory related to the specialty/assignment

·             specific laboratory, and analytical, and interpretational protocols related to the procedures utilized in the PPD/FSB in the area of assignment.

·             forensic quality assurance practices

·             national standards and guidelines related to assigned area

·             city, state, national, international, and/or departmental standards, laws, directives, and guidelines that apply to assignment area.

·             safe and proper handling of hazardous items, such as firearms, biological fluids, acids/bases, flammable liquids, that are encountered within the assignment area

·             safety practices and procedures as they apply to a forensic laboratory related to the assignment

·             policies and procedures related to chain of custody

·             policies and procedures related to expert testimony

·             research methods and techniques

·             basic computer operations




·             the principles of biology, molecular biology, genetics, biochemistry, forensic science, and statistics

·             basic biology and molecular biology techniques and equipment used in a forensic biology laboratory

·             National Standards for Forensic DNA Analysis




·                     the principles, methods, and practices of chemistry, in particular analytical chemistry

·                     mathematics and statistics as they relate to chemistry




·               the principles of comparative analyses used in a forensic science laboratory for   pattern evidence, specific to the area of assignment

·               mathematics and statistics as they relate to forensic pattern evidence

·               reference standards in relation to the area of assignment






·             identifying characteristics inherent in forensic samples

·             independently performing forensic analysis, according to established protocols as a qualified examiner in the area of specialty/assignment

·             utilizing current laboratory equipment and techniques in the assigned discipline.

·             maintaining forensic quality assurance standards

·             safe and proper handling of laboratory equipment, reagents, and evidence to include items of a potentially hazardous nature

·             communicating in both written and verbal form

·             evaluating statistical data






·             independently analyze forensic evidence in the area of specialization or assignment at the qualified examiner level

·             perform technical reviews of analysis and reports

·             prioritize work and meet deadlines

·             enter and evaluate statistical data

·             continually develop and advance expertise in the principles, practices, materials and equipment used in the assigned discipline

·             use and maintain sophisticated equipment in the assignment area

·             perform the tests, examinations and protocols required in the area of assignment

·             express ideas and facts clearly and effectively both orally and in writing

·             distinguish colors and visually analyze analytical results, which may include color changes, pattern recognition, graphs, charts, tables, and other forms of electronic data

·             perform standard tests and make accurate analyses, using quality control techniques

·             establish and maintain effective working relationships with associates and public

·             understand and follow oral and written instructions

·             maintain accurate records and prepare reports

·             testify effectively in court

·            operate a computer console to analyze results of tests or to perform calculations involved in the analysis of evidence


MINIMUM ACCEPTABLE TRAINING AND EXPERIENCE  (The following statement represents the minimum training and experience standards which will be used to admit or reject applicants for tests.  Applications submitted by candidates for this class will be reviewed based on training and experience requirements as approved on 11/14.)




            Completion of a bachelor's degree program at an accredited college or university, with major course work in:


SPECIALTY:             DEGREES               


BIOLOGY:                 Any of the following degrees, which include at least 3 credits in                                           EACH of the following courses: molecular biology, genetics and                                          biochemistry:


1.    Chemistry

2.    Biological Science

3.    Forensic Science

4.    Biomedical Engineering





Candidates must also have, prior to appointment, successfully completed 3 coursework credits or have documented training/experience in population genetics or statistics, in accordance with FBI Quality Assurance Standards.  



1.    Chemistry




      Any of the following degrees with 24 semester hours in chemistry or       biochemistry:


1.    Biological Science

2.    Forensic Science

3.    Physical or Natural Science

4.    Applied Science

5.    Chemical Engineering





1.    Chemistry

2.    Biological Science

3.    Forensic Science

4.    Physical or Natural Science

5.    Applied Science

6.    Engineering




1.    SCIENCE OR NON-SCIENCE DEGREE with coursework in statistics or applied research methods








            Two years of training level forensic science work as a Forensic Scientist 1 or equivalent forensic science work learning the methods and techniques involved in the preservation, examination, handling, and comparative analysis of items of evidence collected in criminal investigations in the assigned specialty/discipline.




NOTE: The following experience satisfies the minimum training and experience requirements:


            Four years of forensic experience in the Philadelphia Police Department or another accredited forensic science laboratory in a sub-discipline of pattern evidence (firearms, latent prints or document examinations)




            Proof of successful completion of a training program within an accredited forensic science organization, which resulted in qualification as a forensic examiner before July 31, 2014. Documentation of qualification as a forensic examiner must be  provided at  time of application. See below for details.


City classes that typically meet these requirements include: Firearms Examiner Series (6C02, 6C04, 6C06, 6C07), the Fingerprint Identification Specialist Series (6C12, 6C13 & 6C14) and Crime Scene Examiner (6C17).


NOTE: Candidates must provide documentation to support their qualification as a qualified examiner. See below for details.


QUALIFIED FORENSIC EXAMINER DOCUMENTATION- Must be provided to the Police Department at the time of interview. Documentation for positions in the Pattern Evidence Specialty being filled by utilizing the note above must be provided at the time of application.


            Proof of successful completion of a training program within an accredited forensic science organization, which resulted in qualification as an expert (forensic examiner) in the area of specialty and assignment.  Qualification must have included independent forensic casework, routine proficiency testing, and testimony as an expert in the area of specialty/discipline. External candidates must provide documentation to support their qualification as an expert.  Documentation should include:


1.            A certificate or letter from an accredited forensic laboratory that details the area and date of qualification.

2.            Proof of the laboratory’s accreditation from either ASCLD-LAB, FQS, or another ISO 17025 forensic accrediting body.

3.            Proof of successful completion of routine proficiency test may include copies of proficiency test results, a summary document from the laboratory’s quality assurance program, or other documentation that details scope and completion of proficiency testing.

4.            Proof of testimony experience may include a copy of a court transcript from one or more trials, or a letter from a court official detailing the expert’s experience testifying in court as an expert in a specific discipline.


NOTE: Employees must maintain status as a qualified Forensic Examiner during tenure of employment as a Forensic Scientist 2.


NOTE: Selective Factor Certification may be utilized, as needed, to fill specific positions. In accordance with Civil Service Regulation 11.032 - Selective Factor Certification - the appointing authority may request certification of eligible candidates with one or more of the required degrees and/or specific experience to fill specific positions in this class. Certification to fill such positions will be made from the two highest-ranking eligible candidates on the eligible list who possess the specified degree and/or experience.




            Ability to physically perform the duties and to work in the environmental conditions required of a position in this class.

            Ability to visually distinguish test results, which may include color changes, pattern recognition, and interpretation of electronic data (tables, graphs and charts).




            Possession of a valid proper class motor vehicle operator's license as issued by the Commonwealth of Pennsylvania prior to appointment and during tenure of employment as a Forensic Scientist 2 if required by work assignment.


Class Established 11/85

Spec. Revisions:

CSC - 4/13

AdBoard - 5/13

Latest Spec. Revisions:

                                                                                                                                        CSC - 9/14

                                                                                                                               AdBoard - 11/14